Treatment of hydrocarbon oils



March 193 5. J. c. MORYRELL ET AL 1,995,005

TREATMENT OF HYDROCARBON OILS Filed Dec. 3, 1931 REACTION CHAMBER\APORIZING FURNACE COKING CHAMBERS FURNACE INVENTORS I JACQUE cg,MORRELL CHARLES H. ANIGELL Patented Mar. 19, 1935 TREATIWENT FHYDROCARBON OILS Jacque C. Morrell and Charles H. Angell, Chicago, I1l.,assignors to Universal Oil Products Company, Chicago, 11]., acorporation of South Dakota Application December, 3, 1931, Serial No.578,751

8 Claims.

This invention relates to the treatment of hydrocarbon oils and moreparticularly refers to an duced pressure zone outside of the maincracking zone and simultaneouslyreforming gasoline or pressuredistillate. This in efiect produces nonresiduum operation outside of themain cracking1 zone and permits lengthening the operating cyc e.

- The principles of the invention maybe applied to practically any typeof cracking system. As an example, one approved form of cracking processto which the principles of the invention are readily adaptable is thetype employing a reaction chamber operated at substantialsuper-atmospheric pressure wherein the total heated materials introducedthereto from the heating element of the system are subjected tocontinued conversion, the vapors from the reaction chamber passing tofractionation while non-vaporous residual oil is separately removed fromthe chamber. Another suitable form of cracking process employs areaction chamber operated at substantial super-atmospheric pressurewherein continued conversion, particularly of the vaporous,

conversion products from the heating element of the system, may continuefollowing which both liquid and vaporous products are introduced into areduced pressure vaporizing chamber to effect further vaporization andcooling of the residual oil and its separation from the vapors, saidvapors passing to fractionation while the residual oil is separatelywithdrawn from the chamber.

According to the principles of the present invention, the residual oilresulting from cracking whether separated from the vaporous conversionproducts under relatively high or relatively low pressure conditions, isdirected to a separate zone preferably maintained at substantiallyatmospheric or relatively low super-atmospheric pressure wherein saidresidual oil is reduced to coke or substantially dry carbonaceousmaterial, assisted by the introduction into said coking 'zone ofreheated distillate from the cracking system.

' One specific embodiment of the invention may comprise subjecting ahydrocarbon oil to conversion conditions in a heating element,introducing the heated materials into an enlarged reaction zone,operating both the heating element and I the reaction zone atsubstantial super-atmospheric pressure, withdrawing both liquid andvaporous products from said reaction zone to a reduced pressurevaporizing zone wherein vaporous and non-vaporous conversion productsare separated,

subjecting the vapors to fractionation whereby their relatively heavycomponents are condensed to be returned to said heating element forfurther conversion, subjecting the relatively light components of thevapors to condensation and cooling and collecting the resultingdistillate and gas, withdrawing non-vaporous residual oil from saidreduced pressure vaporizing zone and introducing it into a coking zonepreferably operated at substantially atmospheric or relatively lowsuper-atmospheric pressure, subjecting a portion or all of saiddistillate resulting from the aforementioned cracking and fractionatingoperations to reheating under any desired temperature and pressureconditions in a separate heating element and introducing the reheatedmaterial into said coking zone wherein it assists reduction of saidresidual oil to coke or substantially dry carbonaceous residue,subjecting vapors from said coking zone to fractionation to efiectseparation of their relatively light and relatively heavy components,returning said relatively heavy components to the first mentionedheating element for further conversion, subjecting said relatively lightcomponents, preferably comprising materials of substantially motor fuelboiling range and gas, to condensation and cooling and collecting theresulting products.

The attached diagrammatic drawing illustrates one form of apparatusembodying the principles of the present invention. The followingdescription of the drawing includes a description of the process of theinvention as it may be practiced in the apparatus illustrated. Raw oilcharging stock for the system may be supplied through line 1 and valve 2to pump 3 from which it is fed through line 4 and may pass, all or inpart, through line 5, valve 6 and line '7 to heating element or, ifdesired, all or any portion of the raw oil may pass from line 4 throughline 8 and valve 9 into fractionator 10. The raw oil supplied tofractionator 10 is preheated by direct contact with the relatively hotvapors in this zone, serving to assist their fractionation and passing,together with their relatively heavy components which are condensed inthe fractionator, through line 11 and valve 12 to pump 13. Pump 13supplies the reflux condensate or reflux condensate and preheated rawoil, through line '7 and valve 14 to heating element 15.

Heating element 15 is located in a furnace 16 of any suitable form andthe oil supplied to this zone is heated to the desired conversiontemperature preferably at a substantial super-atmospheric pressure. Theheated oil is discharged from the heating element through line 1'7 andvalve 18 to reaction chamber 19.

Chamber 19 is also preferably maintained at a substantialsuper-atmospheric pressure and, as

here illustrated, -this zone may be operated in either of two manners.By one mode of operation the materials entering chamber 19 from heatingelement are substantially separated into vaporous and non-vaporouscomponents. The vapors, after subjection to continued conversion in thereaction chamber pass through line 20 and valve 21 to fractionation infractionator 10. Residual liquid products are withdrawn from the chamberthrough line 22 and may pass either through valve 23 to furthertreatment, as will be later more fully described, or through line 24 andvalve 25 to further vaporization in chamber 26. The time to whichnon-vaporous conversion products are subjected to further conversion inchamber 19 will depend primarily upon the level of residual oilmaintained in this zone, a substantial level being maintained whenprolonged conversion of residual material is desired while little orsubstantially no level of residual oil is maintained in the chamber whenit is desired to subject said residual oil to relatively shortconversion time in this zone. The: other'mode of operation possible withthe arrangement of apparatus illustratedin the drawing compriseswithdrawing both vaporous and non-vaporous products from reactionchamber 19 through line 22, line 24 and valve 25 into reduced pressurevaporizing chamber 26. In this manner the va: porous products aresubjected to continued conversion for a predetermined time as they passthrough chamber 19 while the heavier non-vaporous products gravitatemore rapidly to the bottom of the chamber and are removed from thereaction zone substantially as fast as they collect, thereby preventingany substantial further conversion of these products.

In case chamber 26 is employed it is preferably maintained under asubstantially reduced pressure relative to that employed in chamber 19and the non-vaporous products introduced into this zone are subjected tofurther vaporization and cooled by the liberation of heat effected bythe reduction in pressure. Residual oil remaining unvaporized in chamber26 is withdrawn therefrom through line 2'7 and may be removed, in part,from the system to cooling and storage or elsewhere, as desired, throughline 28 and valve 29. A portion or all of the residual oil, however,passes through valve 30, in line 2'7, to further treatment as will belater more fully described. Vapors from chamber 26 pass through line 31,valve 32 and line 20 to fractionation in fractionator 10.

The vapors introduced into fractionator 10, coming either from reactionchamber 19 or reduced pressure vaporizing chamber 26 or in part fromboth, as previously described, are separated into relatively light andrelatively heavy components by fractionation in this zone. atively heavycomponents of the vapors, which are condensed in fractionator 10 pass,as already described, to heating element 15 for further conversion. Therelatively light components of the vapors which may, for example,comprise cracked materials of motor fuel boiling range, together withgas produced by the system, may be withdrawn from the upper portion ofthe fractionator through line 33 and valve 34 to be subjected tocondensation and cooling in condenser 35, dis- The reltillate anduncondensable gas from which may pass. through line 36 and valve 37 tobe collected in receiver 38. Uncondensable gas may be released fromreceiver 38 through line 39 and valve 40. A portion of the distillatemay be withdrawn from the receiver and from the system through line 41and valve 42. A portion of the distillate collecting in receiver 38 may,if desired, be withdrawn through line 43 and valve 44 to be recirculatedby means of pump 45 through line 46 and valve 47 to the upper portion offractionator 10 to assist fractionation of the vapors and to maintainthe desired vapor outlet temperature from.

the fractionator.

Residual oil produced by the cracking system which, depending upon theoperation employed, may be withdrawn either from chamber 19 through line22 and valve 23 or from chamber 26 through line 27 and valve 30, asalready described, passes through line 48 to pump 49 from which it isfed through line 50 and may pass either through line 51 and valve 52into coking chamber 53 or through line 51' and valve 52 into cokingchamber 53' or the residual oil may, if desired, be directed to bothcoking chambers simultaneously. Chambers 53 and 53 are similar cokingzones which may be operated either alternately or simultaneously. Itwill be understood that it is also within the concepts of the presentinvention to employ a single coking zone or any number of a plurality ofsuch zones although only two are illustrated in the drawing.

A portion or all of the distillate fromreceiver 38 is withdrawn throughline 54 and valve 55 to pump 56 from which it is fed through line 5'7and valve 58 to heating element 59 being therein subjected to thedesired temperature under any desired pressure conditions. A furnace 60of any suitable form supplies the required heat to heating element 59.The reheated distillate is discharged from heating element 59 throughline 61 and may pass through any or all of a plurality of lines 62controlled by valves 63 into coking chamber 53 or through similar lines62 controlled by valves 63' into coking chamber 53'. If desired, by useof valve 64 connecting lines 50 and 61, the residual oil and thereheated distillate may be commingled prior to their introduction intothe chambers 53 and 53 in which case the commingled materials may enterthe chambers through any or all of the lines 62, 62', 51 and 51'. In anycase the reheated distillate is intimately contacted in chambers 53 and53 with the resid-.

ual oil, materially assisting its reduction to coke or substantially drycarbonaceous material in the coking zones. Chambers 53 and 53' areprovided with drain lines 65 and 65-respectively, controlledrespectively by valves 66 and 66'. Vapors are removed from chamber 53through line 6'7 and valve 68 while vapors are withdrawn from chamber53' through line 6'7- and valve 68, either or both streams of vaporspassing through line 69 to fractionation in the fractionator '70.

'Vapors supplied to fractionator '70 are separated into relatively lightand relatively heavy components; the latter, which are condensed in thefractionator, being withdrawn therefrom through line 71 and valve '72 topump '73 from which they are fed through line '74 and valve 75 into line7 and thence to heating element 15 for further conversion. 'Therelatively light desirable components of the vapors supplied to frac-'tionator 70, preferably comprising materials of substantially motor fuelboiling range, are removed together with uncondensable gas fromfractionator 70 through line 76 and valve '77, are subjected tocondensation and cooling in condenser '78 from which distillate anduncondensable gas are withdrawn through line '79 and valve 80 to becollected in receiver 81. Uncondensable gas may be released from thereceiver through line 82 and valve 83 while the distillate may bewithdrawn through line 84 and valve 85. A portion of the distillatecollecting in receiver 81 may, if desired, be withdrawn therefromthrough line 86 and valve 87 to be recirculated by means of pump 88through line 89 and valve 90 to the upper portion of fractionator 70 forthe purpose of assisting fractionation in this zone and maintaining thedesired vapor outlet temperature therefrom.

Pressures employed within the system may range from substantiallyatmospheric to superatmospheric pressures as high as 2000 pounds or moreper sq. in. Conversion temperatures employed may range from 800 to 1600F., more or less. Preferably temperatures of the order of 850 to 950 F.or thereabouts are employed in the primary heating element, wherein theraw oil charging stock and reflux condensates are treated, while thisheating element and the succeeding reaction chamber preferably employsubstantial super-atmospheric pressures which may range, for example,from 100 to 500 pounds, more or less, per sq. in. The vaporizingchamber, when employed, preferably utilizes a substantially reducedpressure relative to that employed in the reaction chamber and ranging,for example, from substantially atmospheric to 100 pounds or thereaboutsper sq. in. Pressures employed in the fractionating, condensing andcollecting portions of the primary cracking system may be substantiallyequalized with that employed in the vaporizing chamber or when thevaporizing chamber is not used may be either substantially equalizedwith or somewhat lower than those employed in the reaction chamber.

Temperatures employed in the secondary heating element, utilized forreheating of the distillate, may vary, depending primarily upon the typeof operation desired, over a relatively wide range, for example, from800 to 1600 F., more or less, and the pressures employed in this zonemay also vary over a range of from substantially atmospheric to 500pounds or more super-atmospheric pressure per sq. in. Preferablysubstantially atmospheric pressure or relatively low superatmosphericpressures are employed in this zone when temperatures above 1000 F. orthereabouts are employed. The coking chambers and the succeedingfractionating, condensing and collecting portions of the coking systempreferably employ substantially atmospheric or relatively lowsuperatmospheric pressures, although pressures up to 500 pounds, ormore, per sq. in. may be employed, if desired, when such pressures areemployed in the secondary heating element. 7

As a specific example of the operation of the process of the presentinvention, a 23 A. P. I. gravity mid-continent fuel oil is the chargingstock supplied to the cracking system, it is subjected in the primaryheating element together with reflux condensates from both fractionatorsof the system to a temperature of about 885 F.

A superatmospheric pressure of approximately 275 pounds per sq. in. ismaintained in this heating element and is substantially equalized in thereaction chamber. The vapors are removed from the reaction chamberto-fractionation and little or substantially no level of residual liquidis permitted to accumulate in the reaction chamber. Cracked distillatefrom the fractionator, having an end-boiling point of approximately 550F.,

is subjected in a separate heating element to a temperature ofapproximately 950 F. under a pressure of approximately 600 pounds persq. in. The heated materials are introduced into alternate cokingchambers maintained at a pressure of about 100 pounds per sq. in.wherein they assist reduction of the residual oil from the reactionchamber to coke. This operation may yield approximately '70 percent of400 F. endpoint motor fuel having an antiknock value approximatelyequlvalent to a blend of 80 percent octane and 20 percent normalheptane. The additional products of the system are about 1200 cubic ft.of gas and about 85 pounds of coke per barrel of charging stock. Byreducing the pressure in the coking chambers the yield and thevolatility of the coke may be reduced, the yield of motor fuel beingalso somewhat reduced and the production of gas somewhat increased.

As an example of another operation within the scope of the presentinvention, a 36 A. P. I. gravity Pennsylvania crude oil containingapproximately percent of straight-run gasoline is the charging stock tobe treated. This" material is supplied to the fractionator of thecracking system wherein straight-run gasoline is separated from thecrude, -to be collected, together with the cracked motor fuel producedbythis portion of the system. The topped crude, together withintermediate conversion products from the fractionator of the crackingsystem and reflux condensate from the fractionator of the coking system,are subjected in the heating element of the cracking system to atemperature of approximately 910 F. A substantially equalizedsuper-atmospheric pressure of approximately 400 pounds per sq. in. ismaintained in the heating element and reaction chamber. Both liquid andvaporous products from the reaction chamber are introduced into thevaporizing chamber at a reduced pressure of approximately 50 pounds persq. in. Residual liquid from the vaporizing chamber is introduced intoalternately operated coking chambers. Distillate from the receiver ofthe cracking system comprising straight-run gasoline and crackedproducts of substantially gasoline boiling range, are heated in aseparate heating element to a temperature of approximately 950 F. undera super-atmospheric pressure of approximately 500 pounds per sq. in. andare thence commingled with the residual oil undergoing coking in thecoking chambers. The coking chambers and subsequent portions of thesystem are maintained under a super-atmospheric pressure of about 30pounds per sq. in. This operation may yield a total motor fuel productamounting to approximately 84 percent of the crude and having anantiknock value approximately equivalent to an octane number of 75. Inaddition about 32 pounds of relatively low volatile coke and about 1400cu. ft. of uncondensable gas of high calorific value may be produced perbarrel of charging stock.-

As a specific example of another possible operation, utilizing a 38 A.P. I. gravity Muskegon crude containing approximately v33 percent of badknocking gasoline: this charging stock, including its gasolinecomponents, is subjected in theheating element of the cracking system toa. temperature of approximately 900 F. under a super-atmosphericpressure of approximately 400 pounds per sq. in. A pressure ofapproximately 65 pounds per sq. in. is maintained in the vaporizingchamber, the pressure in the reaction chamber being substantiallyequalized with that in the heating element. Distillate of substantiallymotor fuel boiling range from the receiver of the cracking system issubjected in a separate heating element to a temperature ofapproximately 1600 F. under substantially atmospheric pressure.Substantially atmospheric pressure'conditions arealso maintained in thealternate coking chambers where residual oil from the vaporizing chamberof the cracking system is reduced to a substantially dry carbonaceousresidue by contact with the products resulting from the high temperatureretreatment of the distillate. This operation may produce about 7500cubic feet of uncondensable gas of high calorific value and containing asubstantial amount'of hydrogen. In addition about gal-' lons of arelatively light distillate having an antiknock value approximatelyequivalent to that of benzol and suitable for blending with inferiormotor fuel to improve its antiknock value and lower its boiling pointmay be produced. The coke produced may amount to approximately 28 poundsper barrel of charging stock and may have a volatile content of lessthan 6 percent.

We claim as our invention:

1. A hydrocarbon oil cracking process which comprises heating the oil tocracking temperature under pressure in a heating zone and separating thesame into vapors and unvaporized oil in a separating zone maintainedunder pressure,

separating zone, dephlegmating said vapors to condense fractions thereofheavier than gasoline, separately condensing the gasoline vapors uncondensed by the dephlegmation and collecting the resultant distillate,passing a gasoline-containing portion of said distillate, withoutcontact with said vapors undergoing dephlegmation, through a secondheating zone and heating the same therein sufficiently to increase itsantiknock value, introducing the thus heated distillate to said cokingzone to assist the coking of the unvaporized oil therein, and removingthe vapors from the coking zone and subjecting the same to dephlegmationand condensation.

2. The process as defined in claim 1 further characterized in that saidportion of the distillate is heated to higher temperature in said secondheating zone than is the oil in the firstmentioned heating zone.

3. A hydrocarbon oil cracking process which comprises subjecting the oilto cracking conditions of temperature and pressure in a cracking zone,removing vapors and unvaporized oil from the cracking zone,dephlegmating the vapors in direct contact with crude oil containingnatural gasoline to condense fractions of the vapors heavier thangasoline and thereby distilling the natural gasoline from the crude,supplying the topped into a distillation zone and further distilling thesame therein, passing, a gasoline-containing portion of said distillate,without contact with said vapors undergoingde'phlegmation, through ansaid distillation zone to assist the distillation of the unvaporized oiltherein, and removing the vapors from the distillation zone andsubjecting the same to dephlegmation and condensation.

4. A hydrocarbon oil cracking process which comprises subjecting the oilto cracking conditions of temperature and pressure in a cracking zone,removing vapors and unvaporized oil from the cracking zone,dephlegmating the vapors to condense fractions thereof heavier thangasoline, separately condensing the dephlegmated gasoline vapors andcollecting the resultant distillate, introducing said unvaporized oilwhile still hot into a distillation zone and further distilling the sametherein, passing a gasoline-containing portion of said distillate,without contact with said vapors undergoing dephlegmation, through anindependent heating zone and heating the same therein sufliciently toenhance its antiknock value, introducing the thus heated distillate tosaid distillation zone to assist the distillation of the unvaporized oiltherein, and removing the vapors from the distillation zone andsubjecting the same to dephlegmation and condensation. 5. A hydrocarbonoil cracking process which comprises heating the oil to crackingtemperature under pressure in a heating zone and separating the sameinto vapors and unvaporized oil, rcduc ing the unvaporized oil to cokein a coking zone, dephlegmating said vapors to condense fractionsthereof heavier than gasoline in direct contact with crude oilcontaining natural gasoline thereby vaporizing the natural gasoline fromthe crude, supplying the topped crude and admixed reflux condensate tothe heating zone, finally condensing the mixed vapors of naturalgasoline and cracked gasoline and collecting the resultant distillate,passing a gasoline-containing portion of said distillate, withoutcontact with said vapors undergoing dephlegmation, through a secondheating zone and heating the same therein sufliciently to increase itsanti-knock value, introducing the thus heated distillate to said cokingzone to assist the coking of the unvaporized oil therein, and

removing the vapors from the coking zone and subjecting the same todephlegmation and condensation.-

6. A hydrocarbon oil cracking process which comprises subjecting the oilto cracking conditions of temperature and pressure in a cracking zone,removing vapors and unvaporized oil from the cracking zone,dephlegmating the vapors to con dense fractions thereof heavier thangasoline and to form a gasoline-containing distillate, introducing saidunvaporized oil while still hot into a distillation zone and furtherdistilling the same therein, passing a gasoline-containing portion ofsaid distillate, without contact with said vapors undergoingdephlegmation, through an independent heating zone and heating the sametherein sufliciently to enhance its anti-knock value,

- introducing the thus heated distillate to said dis,-

tillation zone to assist the distillation of the unvaporized oiltherein, and removing the vapors ';from the distillation zone andsubjecting the same to dephlegmation and condensation.

7. A hydrocarbon oil cracking process which comprises subjecting the oilto cracking conditions of temperature and pressure in a cracking zone,removing vapors and unvaporized oil from the cracking zone,dephlegmating the vapors to condense fractions thereof heavier thangasoline, topping crude oil containing natural gasoline by introducingthe same into direct contact with the vapors undergoing dephlegmation,removing from.

the dephlegmating step a mixed natural gasoline and crackedgasoline-containing distillate, introducing said unvaporized oil whilestill hot into a distillation zone and furtherdistilling the sametherein, passing a gasoline-containing portion of .said distillate,without contact with said vapors undergoing dephlegmation, through anindependent heating zone and heating the same therein sufliciently toenhance its anti-knock value, introducing the thus heated distillate tosaid distillation zone to assist the distillation of the unvaporized oiltherein, and removing the vapors from the distillation zone andsubjecting the same to dephlegmation and condensation. Y

8. A hydrocarbon oil cracking process which comprises subjecting the oilto cracln'ng conditions of temperature and pressure in a cracking zone,removing vapors and unvaporized oil from the cracking zone, dephlegmatinand condensing the vapors to form a reflux co densate heavier thangasoline and a lighter condensate containing a substantial quantity ofhydrocarbons boiling within the gasoline range, introducing saidunvaporlzed oil into a distillation zone maintained under lower pressurethan the cracking zone and distilling the same therein by pressurereduction, passing at least a. portion of said lighter con-, densatecontaining gasoline boiling hydrocarbons, without contact with saidvapors undergoing dephlegmation, through an independent heating zone andheating the same therein sufficient- 1y to enhance its anti-knock value,introducing the thus heated condensate to said distillation zone toassist the distillation of the unvaporized oil therein, and removing thevapors from the distillation zone and subjecting the same todephlegmation and condensation.

JACQUE C. MORREIL. CHARLES H. ANGELL.

